这是一道小学六年级的题,请用分数的拆分法做,使运算简便即盼!
參考答案:原式=(2/6+2/24+2/60+2/120+2/210+2/336+2/112)1/2
=(1/1*2-1/2*3+1/2*3-1/3*4+1/3*4-1/4*5+1/4*5-
1/5*6+1/5*6-1/6*7+1/6*7-1/7*8+2/112)1/2
=(1/2-1/7*8+2/112)1/2
=1/4
这是一道小学六年级的题,请用分数的拆分法做,使运算简便即盼!
參考答案:原式=(2/6+2/24+2/60+2/120+2/210+2/336+2/112)1/2
=(1/1*2-1/2*3+1/2*3-1/3*4+1/3*4-1/4*5+1/4*5-
1/5*6+1/5*6-1/6*7+1/6*7-1/7*8+2/112)1/2
=(1/2-1/7*8+2/112)1/2
=1/4